Summary

Section 3134 of the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328) (Sec. 3134) calls for a Federally Funded Research and Development Center (FFRDC) “to conduct an analysis of approaches for treating the portion of low-activity waste (LAW) at the Hanford Nuclear Reservation” intended for supplemental treatment.¹ The U.S. Department of Energy (DOE) has contracted with Savannah River National Laboratory (SRNL), an FFRDC, to provide the called-for analysis. SRNL assembled a team of experts from SRNL and other national laboratories to perform the analysis. Sec. 3134 also calls for the National Academies of Sciences, Engineering, and Medicine (the National Academies) “to conduct a review of the analysis” performed by the FFRDC that is independent of and concurrent with the FFRDC’s analysis “to improve [its] quality.” The complete text of the congressional mandate in Sec. 3134 is provided in Appendix A, and the Statement of Task for the National Academies review is provided in Appendix B.

This review report, the third of four to be issued by the National Academies to address the congressional mandate, focuses on the Statement of Task’s study charge for the committee to provide an “overall assessment.” The committee’s overall assessment is divided into two parts: a technical review (based on the elements in the committee’s Statement of Task) of the FFRDC final draft analysis and a “guide” of the report to aid decision-makers. The committee’s comments in this review report are based on the FFRDC’s final draft report of 278 pages, dated April 5, 2019, and a set of 43 slides produced by the FFRDC and presented at the public meeting on May 16, 2019, in Kennewick, Washington, as well as FFRDC team members’ and others’ public presentations (see Appendix C) at that meeting.

This review report is the final opportunity for the committee to review the FFRDC’s work. It is anticipated that the FFRDC will produce a final report for publication in fall 2019 and that the FFRDC will make use of the committee’s review report in doing so. After publication of the committee’s review report, stakeholders and the interested public will have an opportunity to offer comments on that report and the FFRDC’s final draft report for a period of at least 60 days. The committee’s final task will be to produce a fourth review report that will provide a summary of public comments on the third committee review report and the committee’s views, if any, on these comments and whether they change any of the findings or recommendations in this, the third, review report.

The committee’s overarching task has been to provide a concurrent, independent peer review of the ongoing FFRDC analysis. The committee is neither charged to evaluate the supplemental treatment approaches nor recommend any particular approach. Equally important, the committee notes what is not in the scope of the FFRDC’s analysis and the committee’s review, namely, tank waste management, high-level waste (HLW) processing and treatment, and the Waste Treatment and Immobilization Plant’s (WTP’s) design, construction, and operations. Indeed, the FFRDC does not identify a preferred option for supplemental treatment, but instead in its report, it separately evaluates the treatment alternatives against the baseline, as well as against one another, for a number of factors important to selecting a preferred alternative. The de facto baseline is vitrification of the LAW in the supplemental LAW (SLAW) treatment facility

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¹ According to DOE’s Radioactive Waste Manual, low-activity waste means the waste that remains after as much of the radionuclides as technically and economically practicable have been removed from the tank waste, and that when immobilized in waste forms, may be disposed as low-level waste in a near-surface facility, as long as the waste meets criteria in the Waste Incidental to Reprocessing determination. Supplemental treatment refers to processing of the low-activity waste that is excess to that portion to be treated by vitrification in the Waste Treatment and Immobilization Plant.

because it is the current expectation of many stakeholders and a similar facility (the WTP) is currently under construction to be followed by disposal of the resulting wastes in the Integrated Disposal Facility (IDF) at Hanford. The FFRDC’s task is to provide data and analysis to enable DOE, with congressional oversight, to decide whether to use vitrification, grouting, fluidized bed steam reforming (FBSR), or another treatment approach to treat the SLAW by converting it into a waste form for disposal.

Importantly, the committee notes that the evaluations of treatment options for the SLAW include more than just the solidification of the liquid LAW. The objective of the SLAW treatment is to ensure that the solidified wastes can be permanently disposed of in a near-surface land disposal site. Because these sites have “waste acceptance criteria,” additional pre-treatment processing is sometimes required so that the final waste forms can be accepted for disposal. Additionally, the primary treatment and pre-treatment processes produce “secondary wastes” that also need to be disposed of in a near-surface disposal site. It is this entire process from pre-treatment through treatment to disposal that the FFRDC evaluates and compares.

In addition to the three primary treatment options, the FFRDC also identified two near-surface land disposal options to analyze and compare. The existing IDF located at Hanford is considered as the “baseline” LAW disposal facility, again because it is the current expectation. In this baseline option, the liquid LAW (including SLAW) would be solidified using vitrification, and the secondary waste would be grouted. While both types of waste are slated to be disposed of at the IDF, the Washington State Department of Ecology has yet to approve waste acceptance criteria that would allow for the disposal of grouted secondary waste or even the primary vitrified LAW in the IDF. The second disposal site analyzed is operated by Waste Control Specialists (WCS), and located near Andrews, Texas. WCS is located in an arid and isolated region of western Texas, and it has become an active commercial low-level waste disposal facility in recent years, as well as being designated as a Federal Waste Disposal Facility. The FFRDC report describes the differing, and less restrictive, waste acceptance criteria for WCS as compared with what is anticipated for the IDF and the effect that using the WCS site would have on the SLAW treatment. The FFRDC also mentions the possibility of disposal at the EnergySolutions site near Clive, Utah, and estimates that this site would require removal of almost all of the strontium-90 from the waste stream to meet its Class A low-level waste acceptance criteria.

Using the criteria specified in Sec. 3134, including risks, benefits, costs, schedules, regulatory compliance, and obstacles to implementation, the FFRDC in its report analyzed five alternatives for treating the primary SLAW: (1) vitrification for disposal at the IDF, (2) grouting for disposal at the IDF, (3) grouting for disposal at WCS, (4) FBSR for disposal at the IDF, and (5) FBSR for disposal at the WCS site. The vitrification option would result in significant amounts of secondary waste, which, as mentioned above, would be grouted and proposed to be disposed of at the IDF, although the FFRDC also considers the possibility of disposal of this waste at WCS.

The FFRDC in its report concluded that:

• The vitrification technology would take 10 to 15 years to implement and would cost $20 billion to $36 billion.
• The grouting technology would take 8 to 13 years to implement and would cost $2 billion to $8 billion.
• The fluidized bed steam reforming technology would take 10 to 15 years to implement and would cost $6 billion to $17 billion.

The cost estimates are based on technologies that, for the most part, have not yet been fully developed or deployed, and are based on costs from similar technologies, as well as assuming ideal funding conditions (i.e., no funding caps) and no redirection during a multi-year effort. Thus, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower. The FFRDC team also concluded that a SLAW treatment and disposal option that meets regulatory requirements for disposal can be developed using any of the three treatment technologies evaluated. In addition, the FFRDC report (on p. 22) notes that for some treatment alternatives, “the required time for construction and

startup require an immediate start to allow completion by the required startup date” because DOE’s current plan is a target date of 2034 for the SLAW treatment to begin in combination with the WTP.

The FFRDC and the committee have gone through multiple iterations of draft FFRDC analysis reports and committee review reports, with both formal and informal comments and responses. The committee finds that the FFRDC has generally been responsive to comments, and the most recent FFRDC report has improved considerably over its predecessors in focus, responsiveness to the congressional mandate, and technical analysis. Furthermore, in offering the suggestions in this review report, the committee recognizes that the FFRDC’s work is planned to end in fall 2019. Thus, the suggested improvements are included to aid the reader in interpreting the contents of the FFRDC report and for potential use in follow-on studies.

Based on the committee’s technical review (see Chapter 2 for details) of the FFRDC’s final draft report and the presentation materials from the May 16, 2019, public meeting, and based on the committee’s consideration of the usefulness of the final draft analysis for decision-makers (see Chapter 3 for details), the committee has reached consensus on the following findings and recommendations.

USING THE FFRDC REPORT

Overall Assessment

Finding 1-1

The purpose of the committee’s review is to advise whether DOE, Congress, regulators, and other stakeholders can rely on the FFRDC report to evaluate and decide on a treatment approach for the SLAW. The committee finds that, in its current iteration, the FFRDC’s analysis:

1. When taken alone, does not yet provide a complete technical basis needed to support a final decision on a treatment approach;
2. Does not yet clearly lay out a framework of decisions to be made among treatment technologies, waste forms, and disposal locations; but
3. Can form the basis for further work as described below in the committee’s findings and recommendations.

Analysis of Costs, Benefits, and Risks

Finding 2-1

The cost estimates in the FFRDC report are based on technologies that, for the most part, have not yet been fully developed, tested, or deployed for Hanford’s particular, and particularly complex, tank wastes, and instead use costs from similar technologies. As a result, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower.

Finding 2-2

The cost estimates in the FFRDC report are based on continuing funding at and beyond current levels to optimize the waste treatment technologies and speed of progress. These involve very large annual appropriations, which are inevitably uncertain over the planned decades of activity, especially because current planning assumptions anticipate a two- or three-fold increase in expenditures at certain points in the SLAW treatment process. This, too, introduces the possibility that funding shortfalls will lead to longer schedules, increased total costs, and higher chances of additional tank leaks or structural failures, which will themselves increase costs as well as health and environmental risks.

Finding 2-3

The report’s analysis of costs does not enable the reader to analyze key trade-offs among specific alternatives or variations of major alternatives.

Disposal Risk Assessment

Finding 3-1

Assessment of waste form performance would have to include consideration of the characteristics of the disposal sites and the transport pathways to receptors over relevant periods of time, as well as be based on the inherent characteristics of the waste form.

Finding 3-2

The committee did not have access to the 2017 IDF Performance Assessment (PA) that has been prepared by DOE or to the Performance Evaluation (PE) data and analysis prepared by the FFRDC. Therefore, it was impossible for the committee to critically review the differences in the performance of the three waste forms and their associated disposal systems over time. Additionally, the technical bases for waste degradation models and mechanisms used in the PE analyses for the IDF by the FFRDC team are not well documented and justified.

Finding 3-3

Without the proper supporting documentation for the FFRDC’s PE, or the IDF PA on which it was based, the committee is unable to assess the potential significance of mobile, long-lived fission products such as iodine-129, technetium-99, and other long-lived radionuclindes (possibly selenium-79 and others). It would have been useful for the FFRDC to include the human health risk estimates (dose) over time for all of the long-lived radionuclides that are listed in Table F-2 of their report, not just iodine-129 and technetium-99.

Finding 3-4

The FFRDC report gives little consideration in its analysis to the environmental, health, and safety consequences of hastening or further delaying remediation of the Hanford waste storage tanks, which is related to the probability that additional tank leaks or structural failures will occur over the long period of time expected for the removal and treatment of the waste in the tanks.

Pre-Treatment to Remove Iodine-129 and Technetium-99

Finding 4-1

The FFRDC performed an analysis of whether removal of iodine-129 and technetium-99 was needed to comply with the disposal waste acceptance criteria, and examined the status of technologies for removing these radionuclides from the SLAW feed stream, but the FFRDC report does not respond fully to the congressional direction (in Sec. 3134) because the report does not address immobilization of the iodine-129 and technetium-99 recovered from the LAW as part of the separate high-level glass waste form to be produced in the WTP.

Other Observations

Finding 5-1

The report makes little use of the experience with grouting and other technologies at other DOE sites and commercial operations. While there are unquestionably meaningful differences among the waste forms, technologies, and disposal environments as compared to Hanford, the extensive experience gained at Savannah River Site, in particular, is an invaluable source of insight.

Finding 5-2

The committee was repeatedly told that the selection and implementation of an approach to treat tank waste would be hampered by the insistence by the State of Washington and some other stakeholders that any approach other than vitrification must be “as good as glass.” The term “as good as glass” is not defined in law, regulation, or agreement, and it is only tentatively defined by its advocates. The analysis in, and the public presentations of, the draft FFRDC reports offer a follow-on opportunity for DOE to engage with its regulators and stakeholders to identify performance standards based on existing regulatory requirements for waste form disposal and to pursue a holistic approach to selecting a treatment technology.

Comparisons

Finding 6-1

Over multiple iterations, the FFRDC report has increasingly enabled side-by-side comparisons among the SLAW treatment approaches, exemplified by the table of alternatives and criteria. It remains difficult, however, for the reader to see comparisons and trade-offs in the supporting narrative.

The FFRDC Report’s Steps Forward

Finding 7-1

The report represents useful steps forward by:

1. Confirming that versions of vitrification, grouting, and steam reforming are treatment technologies that merit further consideration for the SLAW;
2. Establishing the likelihood that vitrification, grouting, or steam reforming are capable of meeting existing or expected regulatory standards for near-surface disposal albeit with varying amounts of pre-treatment being required;
3. Highlighting the important contribution of the iodine-129 in the secondary waste streams disposed at the IDF to the total estimated radiation dose rate to the receptors;
4. Underscoring the regulatory and acceptance uncertainties regarding approaches other than vitrification technology for processing the SLAW; and
5. Opening the door to serious consideration of other disposal locations, specifically the WCS facility near Andrews, Texas, and possibly the EnergySolutions facility near Clive, Utah.

Use the FFRDC Report as a Pilot or Scoping Study

Recommendation 1-1

The committee recommends that the “Preliminary Draft” FFRDC report reviewed by the committee (that is, the document dated April 5, 2019) be accepted as a pilot or scoping study for a full comparative analysis of the SLAW treatment alternatives, including:

• Vitrification, grouting, and steam reforming as treatments for the SLAW;
• Pre-treatment to remove iodine-129, technetium-99, and other long-lived radionuclides (e.g., selenium-79) to ensure that regulations are met or reduce cost, and pre-treatment to assure that the waste product meets land disposal requirements;
• Pre-treatment of strontium-90, if it is not removed during the cesium-137 pre-treatment process; and
• Disposal at the IDF, WCS, and (possibly) the EnergySolutions facility.

The draft report should either be substantially revised and supplemented (though the committee understands that the FFRDC team’s funding may not permit this), or be followed by a more comprehensive analysis effort and associated decisional document, which needs to involve the decision-makers or their representatives.

Organize the Report or Decisional Document Around Four Interrelated Areas

Recommendation 2-1

The final FFRDC report or follow-on decisional document should include technical data and analyses to provide the basis for addressing four interrelated areas, as follows:

1. Selection of a technology that will produce an effective waste form. This has two parts:
   • The treatment (immobilization) technology:
     • How well will it work? Is the technology well understood, tested or used under real-world conditions, dependent on other technologies, or relatively simple?
     • What types and volumes of secondary waste are created by each technology?
     • What is the lifetime cost and duration, and uncertainties therein?
     • What are the risks (e.g., programmatic and safety) and uncertainties therein?
   • The waste forms and associated disposal sites:
     • How effective is each waste form in immobilizing the waste (e.g., the materials science of the incorporation, corrosion, and release processes) and over what time periods?
     • What is their performance under the expected disposal conditions (e.g., release from the disposal facility and transport through the geosphere to a receptor)?
     • How do the waste form performances actually differ? This goes further than simply demonstrating compliance, but rather demonstrates an understanding of how the waste forms and disposal environments actually interact.
2. Selection among available disposal sites. The report describes the IDF and WCS, and it briefly mentions the EnergySolutions facility near Clive, Utah. Selection requires an understanding of how each site will “work” over time in providing a barrier to the release and migration rate of key radionuclides, especially and specifically technetium-99 and iodine-129.

Important site-related issues include regulatory compliance, public acceptance, cost, safety, expected radiation dose to the maximally exposed individual over time, and differences among the disposal environments.

3. Determining how much and what type of pre-treatment is needed to meet regulatory requirements regarding mobile, long-lived radionuclides and hazardous chemicals, and possibly to reduce disposal costs. The congressional charge specifically mentions technetium-99 and iodine-129, but other long-lived radionuclides, such as selenium-79, may be relevant. The analysis should consider both:
   • Leaving the technetium (Tc), iodine (I), and other long-lived radionuclides in the waste form for the SLAW, with possible use of enhanced engineered barriers such as getters, which are added materials that can better retain the contaminants of concern; and
   • Removing the Tc and I (and possibly other radionuclides) to create a new waste stream with its own (and possibly different) form of immobilization and final disposition, including incorporating it into the separate vitrified HLW stream.
4. Other relevant factors. Other factors that would affect the selection of a SLAW treatment alternative include:
   • The costs and risks of delays in making decisions or funding shortfalls in terms of additional resource requirements and the increased chance of tank leaks or structural failures over time, and the need to address the consequences (notably, all 149 single-shell tanks have exceeded their design life and the 28 double-shell tanks will have exceeded their design life before the waste is slated to be removed);
   • DOE’s proposed reinterpretation of the definition of HLW waste could change the SLAW size and performance requirements by altering the feed volume and composition depending on how the reinterpretation is implemented;
   • Thorough consideration of the experience at other DOE sites (e.g., Savannah River Site) and relevant commercial facilities; and
   • Outcomes of DOE’s proposed Test Bed Initiative, the second phase of which would have involved (and perhaps still could involve) grout treatment of 2,000 gallons of LAW and shipment to WCS (the first phase involved a proof of concept treatment of 3 gallons of LAW that was sent to WCS and was completed in December 2017). The future of the second phase of the Initiative is now in doubt due to DOE’s withdrawal in late May 2019 of the state permit application.

Need Direct Comparisons of Alternatives to Aid Decision-Making

Recommendation 3-1

The analysis in the final FFRDC report and/or a comprehensive follow-on decisional document needs to adopt a structure throughout that enables the decision-maker to make direct comparisons of alternatives concerning the criteria that are relevant to the decision and which most clearly differentiate the alternatives.

Consideration of Parallel Approaches

Recommendation 4-1

The FFRDC report could also provide the springboard for serious consideration of adopting an approach of multiple, parallel, and smaller scale technologies, which would have the potential for:

1. Faster startup to reduce risks from tank leaks or structural failures if adequate funding is available to support parallel approaches;
2. Resilience through redundancy (like the parallel uranium enrichment and plutonium separation methods during the Manhattan Project);
3. Taking positive advantage of the unavoidably long remediation duration to improve existing technologies and adopt new ones; and
4. Potentially lower overall cost and program risk by creating the ability to move more quickly from less successful to more successful technologies, with less stranded cost in the form of large capital facilities that are inefficient or shuttered before the end of their planned lifetime.